The invention discloses an enhanced high electron mobility transistor and a manufacturing method thereof, which mainly solve the problems of low threshold voltage and complicated process for realizing high breakdown voltage in existing power switching devices, which include: a substrate (1), Transition layer (2), barrier layer (3), gate groove (4), drain groove (5), P-type layer (6), P-type drain column (7), gate column (9), source electrode (11 ), mesa (14), gate (15) and passivation layer (16). An N-type column column (8) is arranged inside the grid column; an array hole (10) is provided in the barrier layer on the left side of the grid column and in the barrier layer on the right side of the P-type drain column; There is an ohmic contact (12), and the P-type drain column and the ohmic contact together form a drain (13); a composite plate (17) is arranged on the upper part of the passivation layer; and a protective layer (18) is arranged on the periphery of the passivation layer and the composite plate. The invention has the advantages of simple process, good forward blocking and reverse blocking, high threshold voltage, and can be used as a switching device.